Construction and roofing of buildings for exhibitions and like purposes



F. w. LANCHESTER.

CONSTRUCTION AND ROOFING OF BUILDINGS FOR EXHIBITIONS AND LIKE PURPOSES.

APPLICATION FILED MAR. 16. 1920.

' 402,077 Patented Jan. 3, 1922.

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, BY 34 JZWWMQ ATTORNEY F. W. LANCHESTER. cousmucnou AND ROOFING 0F aunomss FOR EXHIBITIONS AND LIKE PURPOSES. APPLl CATION FILED MAR. 16. I920.

1,402,077, Patented Jam-3, 1922.

F5 2 G4 G? F5 R F. W.'LANCHESTER.I

CONSTRUCTION AND ROOFING 0F BUILDINGS FOR EXHIBITIONS AND LIKE PURPOSES APPLICATION FILED MAR. 16, I920.

Patented Jan. 3, 1922.

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. aaamwll IN/IIENTUR' lrzmzmuwster,

ATTORNEY F. W. LANCHESIER. CONSTRUCTION AND ROOFING 0F BUILDINGS FOR EXHIBITIONS AND LIKE PURPOSES.

' APPLICATION FILED MAR. Is. 1920.

1,402,077. Patented Jan. 3,1922.

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INVENTOII I H .1; anaheabrr,

ATTORNEY F. w. LANCHESTER. CONSTRUCTION AND ROOFING 0F BUILDINGS FOR EXHIBITIONS AND LIKE PURPOSES.

APPLICATIQN FILED MAR. I6. 1920- Jan.

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mwimon ILWIazmhester BY M I ATTORNEY F. W. LANCHESIER. CONSTRUCTION AND ROOFING 0F BUILDINGS FOR EXHIBITIONS AND LIKE PURPOSES.

APPLICATION HLED MAR, 16, 1920- 1 1,402,077, Patented Jan. 3, 1922.-

I H SHEETS--SHEET 6.

B1 I j Egan. I INI IINIIIII ATTORNEY F. W.-LANCHESTER.

CONSTRUCTION AND ROOFING 0F BUILDINGS FOR EXHIBITIONS AND LIKE PURPOSES.

APPLlCATlON men MAR. 16. 1920.

1 ,402,077 Patented Jan. 3, 1922.

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zmzimewmvfimmz BWMMTORNEY F. -W. LANCHESTER. CQNSTRUCTIO'NZANDROOFING 0F BUILDINGS FOR EXHIBITIONS AND LIKE PURPOSES.

APPLICATION FILED MAR, 16. 1920- 1,402,077, Patented Jan. 3, 1922.

H SHEHS-SHEEI H.

INVENTOR F. W. LANCHESIER.

CONSTRUCTION AND ROOFING 0F BUILDINGS FOR EXHIBITIONS AND LIKE PURPOSES.

APPLICATION FILED MAR1I5| 1920.

I I SHEEISSHEE 9.

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INVENTOR 1 Jmnchestzw BY @(AQJM ATTORNEY F. W. LANCHESIER.

CONSTRUGIION AND ROOFING 0F BUILDINGS FOR EXHIBITIONS AND LIKE PURPOSES.

APPLICATION FILED MAR. I6. I920- 1,402,077, Patented Jan. $1922.

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I! II D uIImI .IIIJIIL I I u n. B 5 5 5 IIII'IIIII N um i lNVIiN-TIIR lifllianclwsbez BY 5K4? M ATTORNEY F. W. LANCHESTER. comsmucnom AND ROOFING 0F BUILDINGS FOR EXHIBITIONS AND LIKE PURPOSES.

APPLICATION FILED MAR 16, 1920. 1,402,077. Patented Jan. 3, 1922.

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BY JP, a um AT TOR N EY stares rarest FREDERICK VJILLIAM LANCI-IESTEB, or nonnon, ENGLAND.

CONSTRUCTION AND ROOFING GE BUILDINGS F93 EXHIBITIONS AND LIKE PURPOSES.

Specification of Letters Eatent.

Patented Jan. 3, 1922.

Application filed March 16, 1920 Serial No. 386,291.

To all whom it may concern:

Be it known that I, Fnnonmon lVILL-Liir LANorinsrnn, a subject of the King of Great Britain and Ireland, and residing at 41 Bedford Square, London, lV. C. 1, England, have invented certain new and useful lmprovements in the Construction and llooiings of Buildings for Exhibitions and like Purposes, of which the following is a specification.

The present invention consists of improvements in the construction and roofings of buildings for exhibitions and like purposes and refers more particularly to an improved construction of roof of a temporaryor semipermanent nature and to improvements in the construction and accommodation of the more permanent or solid parts of the building directed to adapt same to the new type of roof structure.

The present invention consists in brief in a. method of building construction in which the roof weight and weight of the walls or wall structure, or at least part thereof, is borne by air pressure and distributed over the whole ground surface of the inclosed or roofed-in area.

The present invention further consists in building comprising in combination a wall or walled structure and a flexible pressuresupported roof.

The present invention further consists in a flexible dome or other form of roof adapted to be supported by internal air pressure in which the anchora e of the roof tension members is secured by structure (as masonry or concrete or reinforced concrete) of a permanent character forming and formed by the walls, or buildings or some of them, and a means of supplying air under pressure.

The present invention further consists in a dome or other form of roof in accordance with the preceding clause in which thereof structure comprises a fabric of low permeability to air retained by a network system of roping whose terminal members are adapted to be secured by the anchorage provided and comprising an air lock or equiva lent means of ingress and egress appropriate to the purpose for which the building is required.

The present invention further consists in a dome or other form of roof in accordance with either of the preceding clauses in which a retaining rope-work net is provided comprising circumferential members disposed like parallels of latitude and of radial memdisposed after the manner of meridians of longitude, the said radial m mbers, which bifurcate and sub-divide are functionally continuous, and are attached at their outer extremities by appropriate anchorage to the building walls or masonry and are united centrally in common as to a hoop or lantern, for the purpose of retaining and supporting against internal pressure a canvas or fabric envelope of low air permeability.

The present invention further consists in a dome or other form of roof constructec in accordance with either of the preceding clauses in which the masonry construction comprises a number of sections or blocks on independent foundations connected by ternporary wood work, masonry or the like, to be readily capable of renewal as a provision against uneven or irregular settlement, and in the case of a dome forming a continuous compression belt to resist the inward tension of the roof members.

The present invention further consists in a dome or other form of roof constructed in accordance with the first or second of the preceding consistory clauses in a reinforced masonry or ferro-concrete construction comprising vertical bars or foundation bolts with i or without horizontal or inclined bars for fixing an anchorage member or chains by means of which the roof tension members are secured.

The present invention further consists in a dome or other form of roof constructed in accordance with the first or second of the preceding consistory clauses in the provision of entrance or exit passages having as low a ceiling height as possible adapted to be effectively or approximately blocked or sealed by people making use of the said passages en mass-e.

The present invention further consists in a dome or other form of roof constructed in accordance with the first or second of the preceding consistory clauses in the details of construction and accessory features hereinafter described. I

In erecting a roof constructed in accordance with the present invention, the envelope is laid out on the ground in readiness; the net work or rope system, resembling the web of a spider, is laid thereon withthe lantern in the central position and the ropes are at tached to their respective lugs. The en-' 7 present invention, and

velope is then raised. to 'thei'top ofthesurcircumferential rope or eye-bolts arranged to, receive it; the margin itself hangs as a curtain against the Walls and may be lacedthereto to form a pressure tight joint. The

air pressure is then admitted and the dome assumes the erected form for which 1t has been designed;

illustrative drawings which I are diagrammatic and in which like letters refer tolike parts throughout. I

Figures 1 and 2 show in sectionalelevation and'plan respectively adomed building constructed in accordance with the presentinvention.

Figures 3 'and tishow in section and. plan a methodof anchorage ofthe ropenetwork to the masonry and of the lasing oit'the fab- 7 ric roof to secure weather prooiness and I pressure seallng.

Figure 5 illustrates in sectional'elevation the arrangement of the bar work or reinforcement to support the dome anchorage where apertures or doorways are required in,

the inner wallof the building- Figures 6 and 7 give in section and plan (partsection) respectively the construction of the rim of a lantern to occupy the central portion of the dome in accordance Figures 8 and 9 represent in section and plan a portion of the said lantern to a smaller scale.

These figures illustrate a manner in. which the network i of the. dome structure is attached to theflantern aforesaid, alsoprovision for so applying the-roof ing fabric and the lantern fabric as to secure drainage. V I V Figure 10 represents in section an alterna 'tive construction of rim. I V

Figures 11 and 12 represent an elevation. and plan the applicationof a domed roof constructed in accordance with thepresent invention to a covered lawn-tennis court, the

dome as shown being'in the region of 160'- feet diameter.

Figures 13 and I4 and 15 give three views illustrating the detail fitting of the ropes work. 7

Figures '16 and 17 are illustrative of the 7 means by which the designer may control the shape of a domed roof and r Figure 18 is a diagram illustrative of the method by which stress calculations'may be made I Figure 19 represents in block plan'a large exhibition hall and shows'more particularly details relating to the air {supply and! venti lation system.

Figure 20 is'a turalf treatment. 1

with the.

'partelevation of the same: building showing an appropriate architecf V Figure 2 1 is a portion ofthe: same build- 'ends,the roof being in part approximately cylindrical and in part approximately spheri- Referring to the accompanying sheets of grammaticallyshown in plan.

Referring now to the figures in detail the elements or sections of thev building illustrated in Figures. 1 and 2-A A A A etcr-are constructed individually of ferro concrete or masonry and their aggregate weight. is sufficient to more than withstand" the upward component of the maximum pressure to which the. areaof the dome is subjected; Where the foundation is sufli- 'eiently reliable,or where it has been car ried downwto an adequate depth, these var ous'sectlons may be built as oneintegral structure, but'where no adequate foundaf tions areprovided'and' especially in thecase of a dome of'very large dimensions, say 500 or 1000 feet diameter, the individual sections arebuilt each on its own concrete raft or foundation and separated from its neighbour by sufficient space to allow for any possible irregular settlement; these spaces K between the se'ctionsof the ring of buildings being 'filled with temporary masonry or woodwork. The ropework structure of the dome, is anchored, in a manner that will. be hereinafter described, to the various sections of the building aforesaid, and'whereas the vertical. component of the tension due to the pressure within thefdomeis resisted, as

7 already stated by the'weight of the masonry,

thehorizontalfcomponent of the tension, which in the case, of a circular dome is radial, is resisted by the ring of building in compression. It is therefore necessary to provide compression blocks in the spaces K,

K, between the various members of the building structure adequate to take the sin cumferential stress in question.

These may take the form of concrete or stone blocks or. wedges, or in certain cases alternatively timber blocks or Wedges may be employed. The latterare more suitable where considerable settlements or change of level in the foundations are anticipated.

The rope network consists of a number of circumferential members, B B 13, etc., and a number of radial, or approximately radial, membersf'C C20 (1*, etc. The number of the circumferential members 13 B etc, will vary'withthej size of the dome and the degree to which it isdesired to controlitsiorm. Sincethetension on any set of radial members lying between any two adjacent circumferential members is constant, say the members C lying between B and 13 the form of the dome between the said circumferential members is determined and it can be shown mathematically to lie on the surface of a solid of revolution approximately defined by the dotted line D in Figure 1, and an adjacent annular portion of the dome between the circumferential members B and 13 will likewise lie on the surface of a geometrically similar, but larger solid of revolution indicated by the dotted line D The form of these curves is more accurately laid out in Figure 16. By varying the length of the radial member C C C C, etc., or by varying the diameters of the adjacent circumferential menubers the general form of the dome may be controlled and, although for any given initial angle of slope it cannot be made flatter than indicated by the dotted line D (which is the form the dome would assume if no circumferential members other than B were provided) it can be built up to any desired altitude that architectural or other considerations may require. The designer may conveniently employ a number of templates of different sizes, such as indicated in Figure 16 as an aid in determining the proportions required for the different lengths of the radial members, and for the positions and lengths of the circumferential ones. of the network included between the members C C G etc., and B B 13 etc., are structurally spanned by the roofing fabric and the latter must be of suiiicient strength or be reinforced by small mesh network, or supplementary tension members or ratlins may be employed (as described later with reference to Figure 13) to carry the pressure over the maximum of these panel spaces. In order to regulate the width of these panel spaces appropriately each radial member C in the annular element next the central lantern E is arranged to bifurcate as indicated at C and again as indicated at C These bifurcations may be arranged to take place in alternate annular elements or otherwise as may be expedient for the purpose stated.

11 appropriate method of anchorage of the dome network aforesaid is illustrated in Figures 3 and 4. The concrete walls G and roof G which form part of the buildings A A A etc., are furnished with iron or steel reinforcements; certain of the bars are of hairpin form, examples being given at F and F these being brought together in the manner indicated to secure the bar or rod F arranged circumferentially to the building. These bars F in turn serve as an anchorage for a chain or equivalent member of which the terminal links are F and The areas between the meshes F Four links are shown. These chains are arranged to correspond with the terminal radial members C to which they may be conveniently attached by lanyards F or rigging screws thereby enabling the tension to be adjusted. The roof structure G is furnished with upward projections G and G the space between which forms a rain water gutter and the roof fabric H is ar ranged with a fold at H held by lacing H and eye-bolts G set in the concrete masonry. The edge of the fabric or flap H is brought down inside the wall and laced to eycbolts G. This flap serves to secure pressure sealing. It will be seen that the drainage from the roof fabric H is delivered well beyond the lip of the concrete projection G and carried away by the rain water gutter G The down spouts may be conveniently arranged at the extremities of each component between the blocks A A A etc., leading to a drainage system laid below the ground level.

The arrangements of the bars F in Figures 3 and 4 requires that the wall G should be continuous, at leastfor a considerable depth below the eaves. There are cases where this is objectionable as for example when it is wished to provide for an entrance lock of considerable size, or again where an upper tier of sunk boxes is required to be 'a feature of the auditorium. In such cases the construction is modified in the manner indicated in Figure 5 where the bars F and F are coupled to a bar or linkage system F F and anchored vertically to heavy bars F which may form foundation bolts embedded in the pillar structure separating one aperture from its neighbour. Between pillar and pillar an arched member or catenary bar or chain F v is provided to which the intermediate anchorage bars F are bolted or riveted. The bars F and F in Figure 5 serve to locate the circumferential bar F to which the anchorage chains attach as in Figure 3.

The central lantern E Figure 2 which serves as an anchorage for the inner radial members C is shown in detail in Figures 6, 7, 8, 9 and 10. Its general construction resembles that of a wire wheel as apparent from Figures 8 and 9 of which 8 is a part section and 9 a part plan. Here a central hub of drumlike form E and rim E are connected by an upper and lower set of radial construction spokes E and E which form together the structure of the lantern.

The radial rope members C connect to the lugs which may be conveniently arranged in line with the pairs of construction spokes E Ff" each to each. The vertical and horizontal sections of the rim given in Figures 6 and 7 serve to better illustrate the details of construction. The bracket E may be designed to receive the nuts E by which the spokes are tensioned.

spokes E 1s provided to contain the covertion.

mg fabric E the spokes E being carried oil an extension of the bracketE by the pin E the fabric beinn drawn taut bv lacing E from the same extension. The main dome fabric lying beneath the radialrrope members C 1s laced to lugs E by a lacing E". 'The lantern fabric E is furnished with a sealin g strip 13 to prevent air leakage. The rim element of the lantern E may be made in steel of a box'section as shown in l iguresfi and 7 or it may alternatively be constructed of wood after the manner indicated in Figure 10.

The lantern fabric l3 maybe transparent or translucent, for example oiled silk may be employed, the fabric itself being given additional supportby network or additional wire members radial or'circinnierential or both, as indicated at E, Figure 9.

may be glazed in the usual way either with 1 1 -w on a. re. vu. it. l lt el tgl sso ell lo 1 A11 example 1s given in Figures 11 and 12 of the application of the present invention to otlicesy entrance, turustile, etc.;.a squirrel cage air lock (such as commonly fitted to hotels and public buildings) L providing ingress and egress to the enclosure. The en closure is shown in plan as providing two double tennis courts and seating accommoda- Air inlets are provided, such as L in the floor of the building served by underground conduits from the blowing engine. These conduits are indicated by dotted lines.

The pressure required merely to sustain such a roof as illustrated in Figures lland" 12 is but a fraction of an inch water gauge and under ordinary circumstances half an inchor an inch water gauge is more than adequate to sustain the root and impart a sufiicient degree of rigidity. The power required depends upon this pressure and upon the volume of air supplied per min-' ute. Thelatter is determined by the amount of leakage permitterhnamcly the permeability otthe fabric to air under pressure and such accidental leakages as may otherwise exist. There is no ditticulty in ensuring that a root shall be nearly pressure tight, but as itis desirable and necessary to ensure an appropriate degree of ventilation a fabric with a certain degree of permeability 1s preferred. An expenditure of aboutone horse power is suliicient to maintain the pressure and secure adequate ventilation for such a An additional set oi.

ihltcrna- Lively portions or the whole of thelanteru .ri. V inear?" building and purpose as that depicted. In

the event of the permeability of the fabric being too great it may be diminished by ap-' plying dope, paint or varnish either internally or externally and in any case an external coat'ot weather resisting paint, such as used on the envelope of kite balloons and dirigibles is desirable.

An appropriate system of rope work is shown in greater detail in Figures 13, 1 1

and 15. Here two adjacent circumferential members B and B are shown. These are jointed in the mannerilustrated, the ends are looped, spliced .and'served in the customary nautical manner, the loops being' coupled by a link consisting of a pair of plate members M bolts M and sleeves or bushes M Each circumferential member may consist of a single length of wire rope so coupled or may consist of more than one length with couplings at appropriate intervals; The

radial members (3 ,0 C which correspond in disposition to those shown inFigure 2,

are under normal conditions of much less diameter, the individual tension sustained beingmany times lessthan that borne by the circumferential members. The radial ropework conveniently consists of a number of separate elements such as C Figure 1i the ends being loopech' "spliced, and served and the looped ends being made big enough to pass'over the looped coupling ends of B B2 etc. and'the ropework'thus prepared consists of a number of looped and spliced lengths which can be assembled without any subsequent splicing or skilledworkmanship. Effective continuity is given as between C and C? by the points at which these mem bers are attached to 13 B respectively being approximately coincident, the looped ends f O. and C ,.and C and- C being brought in close juxtaposition and being held by seizing so asto be incapable of being displaced. In order to control. the elements 6 C and C etc. at points intermediate be tween their attachment to 13 ,3 etc. interinediate'lincs or. ratlins b are provided, these b'eing'conveniently of hemp or manila and secured to the elements C C G etc, by a clove hitch or other system of knotting. 'The ratlins Z) incidentally serve to better retain and support the roof fabric and they may be arranged more closely than would otherwise be necessary inorder to better perform this function. 1

It hasbeen stated but in a circular domewhere no circumferentialelementsbe provided other thanB in Figure 2 the form of root is determined by the equilibrium curve assumed by the radial rope elements. Neglecting thedefiection due to the weight of the roof itself the equation of this curve is identical with that of an elastic rod bent by a bowstringuntil its ends are parallel; a form well known to mathematicians is plotiaoaow ted with approximate accuracy in Figure 16 in which a number of plottings are given. The portion of a roof in between adjacent circumferential members may be regarded as belonging to one or another of these curves, the axis OY being understood to coincide with the vertical axis of the circular dome. Thus if it be required to construct a dome of spherical form Figure 17 as for example when using a portion of a dome as an end to a cylindrical roof as in Figures 22, 23, a transparent template or tracing of Figure 16 may be applied, as has been done in Figure 17 to define a series'of elements which taken together shall approximate to an arc of a circle. The number of plottings in Figure 16 has been limited for the sake of clearness; if required a number of intermediate curves may be inserted between each adjacent curve given in the figure. With such a; template any desired form Within reason may be given to the circular dome and the lengths and positions of the radial and circumferential memhers may be prescribed with ease and approximate accuracy. The principal stress calculations in the design of a dome in accordance with the present invention relates to the determination of thetensions on the different radial and circumferential elements. The equations for this are simple and may be given with reference to Figure 18.

Let r be the radius of the point p from the axis OY.

Let 6, and 6 be the angles made by the radial elements as in Figure 18.

Let a be the number of radial members.

Let P be the air pressure in pounds per square foot then Tension on each radial member in pounds igures 19 and 20 represent in part plan and elevation a large circular domed exhibition hall and Figure 19 more particularly illustrates the air pressure and ventilation system. The diameter of the dome contemplatel in this design is in the region of Oil-feet.

In Figure 19 airways or culverts are provided underground by cut and cover as indicated by dotted lines. The system comprises a circumferential channel V and radial channels V Air is fed to the distribution system'from fans or blowers V through expanding conduits V The air may be delivered to the building through gratings or through a number of shafts V V projecting some few feet above the ground level, the

latter being preferable as not tending to throw up dust. In order that the incoming air may be warmed heaters may be provided as indicated at V, as shown; these as illustrated are intended-to be of honeycomb type heated by exhaust steam.

In a building such as that under consideration a large proportion of the building proper is required for various services such as exhibition booths, oflices, etc., which require to be in free communication with the domed area. These therefore form part of the pressure system and "are furnished with ventilation conduits represented diagrammatically by V V and V Ventilation egress from the building is provided by percola-tion through the fabric dome and by leakage and when desired by regulated apertures from the subsidiary halls, oihces, etc. In cold weather when the heating apparatus is in action it is so regulated that the air is delivered to the dome at approximately the temperature which it is required to main tain. It is one of the advantages of the present system of roofing that there are no down draughts of cold air and that there is no loss of heat other than the actual warm air lost by percolation through the roof. In

roofing of ordinary construction heat requires to be delivered to the building sufficient not only to allow for the loss by hot air passing away through windows or other outlet channels but also to reheat'air'which has been cooled by contact with the roof, and it is well known that down draughts of cold air are commonly experienced. In a roof constructed in accordance with the present invention the egress of air necessary to permit of appropriate ventilation takes place by percolation through the roof fabric, and there is no other loss than that of the heat carried away by the air in the act of leakage. In other words it is the air chilled by contact with the roof that passes out and thus the roof acts as though it were a perfect nonconductor of heat. From the above it follows that the heating capacity required for the dome portion of the building may be calculated from the volume of air deemed necessary for the purpose of ventilation and from the temperature rise which is desired.

The scheme as exemplified in Figures 19 and 20 comprises the usual necessities such booths or offices 1 1 (Figure 21) communicating with the domed inclosure, refreshment bars as N dining halls, etc, indicated by N N N staircases givingaccess to. gallery accommodation such as N 'a grand entrance N (Figures 19 and 20), boiler and power houses N with chimneys of decorative char; acter N The power houses serve to enerate current to supply the electrically driven fans V and for lighting and power purposes within the hall, and waste steam is used when required in the heating apparatus V".

v upper belt containing the root anchorage, in

In a building of the size in contemplation the foundation question becomes important and the advantage ofthe flexible root as tolerantof small degrees of settlement is the more manifest. Relating to F gure 21 itwill be seen that the various sections of the buildin such as those comprising accommo- .dation 11 and N iand the lesser blocks be tween these, may each be built on its own ioimdation independent of its neighbour with 1ntervening spaces' K K filled with separatedrfroin the adjacent buildings by spaces 19,11 likewise filled with temporary .masonry. As in the previous description an adequate abutment of a solid character is provided between the inner walls of the ldifierent sections, more especially at the order to take the inward component of the root tens10n,but this 18 only necessary to the extent that the buildings themselves" may be inadequate to individually stand the strain.

The drainageof'each roof section is conveniently ,made independent of its neighbours and. the down spouts or conduits may be conveniently housed within the spaces K K etc, and carried to a drainagesystem laid underground. v r In the designllustrated in Figures 19,

20 and 21 a large air lock may be conve11-' iently arranged in the building :sectiondiametrically opposite that containing the grand entrance N, the construction of such a lock will be described with reference to a later figure. V

The emergency exit forming a subsidiary part of the present invention may be prothe authoritiesat as many points as desired, any block' section of the building being adaptable to this purpose. The construction or more people abreast. Egress is controlled by doors opening outwards at the exit end of the passage and such doors may be so constructed tobe released automatically by .suilicientpressure from within. Each emergency exit'may comprise one or more passages as described arranged parallel and adjacent one to the other. hen in use the mass of people leaving by any exit passage issulficient to prevent any serious escape of pressure a r, and the doors of the passages not inuse may he closed or. as the passages cease to be occupied they. may be closed in people;

a radial.

comes vertical or nearly vertical.

hall such as illustrated in Figures 19 and 20 the existence of anaperture of considerable area is not ordinarlly a matter of grave importance but the need for conserving the and consideration ina smaller building. An

emergencyiexit maybe built to alternatively act asan air lock, an inner set of doors being provided to be used when required but normally to remainopen.

An emergency exit built or constructed in accordance with the foregoing description may be used in case of need as a means of entrance tor'large' numbers or masses of In such cases control is eliected from the inner doors which are not opened until the corresponding passage is crowded to the necessary degree to secure adequate sealing.

In a large ball such as depicted in Figures 19 and 20 it is sufficient for the purpose of ventilation if the measure of the air supply be based on the conventional assumption that the total air isreplacedonce every three hours or thereabouts even, where the number of visitors admitted is up to the full capacity of the hall. The height of the dome is in the region of 200-i'eet and even were the prestritugal fans any one of which alone is capvided in accordance with the requlreinents of able of supporting the roof;

But the sustentation of the roof may trequently be effected without the employment of mechanical power. In the event of a .wind'ot some ll) or 50 miles an hour a suittheirlcss weight per square foot area can be sustained on a lower natural wind velocity. It isonly possible to use natural wind to; the sustaining o'ta roof so long as the design of the dome is appropriate, namely the dome must be oi comparatively flat form and in no part so steep that the fabric be- VVhen it is desired to use natural wind pressure as an auxiliary means of sustaining a roof the collecting cowl requires to'be carried at a considerable distance above the ground surface, a vertical shait or chimney be ng built order to conserve the. pressure. In a large ofadequate height. The delivery irom this shaft may be carried into the building by an independent channel or may be arranged to communicate with the suction side of one of the pressure feeding fans, in the latter case even when the wind is insuiiicientitself to maintain the root its pressure will be utilized to minimize the consumption of power required. In applying auiriliary wind inflation to the support of the dome in Figs. 19 and 20 a separate shaft and cowl may be fitted to the intake of each of the :tour electrically driven tans W, V those for the time being to the windward side of the building being utilized. Valves are fitted to control the ducts V, V adapted to be closed in order to prevent the escape of air by way of the fans and shafts not for the time being in use.

ln Figure 22 an exhibition building having a roof elongate form is exemplified. The root consists of a cylindrical portion the equilibii section of which is the arc of a circle and terinal ends of nearly spher1- cal form. The sphere ap roximated in the manner illu tratcd in Figure 1? in order center the cvlino" A. distribution 6r booths 1A is given appropriate to xh' :ition building of this typ e, but equally applicable as bones and *anged in tweiticrs when 1t is inat the building should be used for such purposes as military tournaments or as a stadium. Subsidiary halls N are proled suitable to serve as refreshment bars or dining room and by way illustration a small cinema theatre or concert room 1S illustrated at N. The whole of the booths N N etc. and halls N N and l" communicate with the pressure system aid therefore permit of tree access with the domed area or ring. in air lock is indicated at N suitable to give access for large exhibition units such as aeroplanes etc, or capable of dealing at once with considerable numbers ot motorcars, horsemen or troops or for the more rapid evacuation of the building at closing time. in detail the air lock N comprises a double gateway oi sui' ncient width for whatever purposes may be required, commanded at its ingress and egress by t o sets or sliding doorsmounted on anti Friction rollers; these doors are arran ed in pairs and figures N N and N N the external doors are shown closed id. the internal doors are shown open, the wings N are not movable but form screens behind which the doors N and N are nested when thrown open. The width or" one look internally is conveniently made wider than the ingress and egress apertures in order to permit of convenience in handling diihcult units or to give greater cain the manner a The architectural features as to accommotion etc, are depicted in Figures 22 and in the bar-est outline, suggestion also in. ven of the subdivision oi the building into cc 1 units, the contir ty or" the structure being orolren at w i 1,.f! v w- SUZllULL by temper K the gaps being masonry or woodwork ady tbscribed. In the n l igures 22 and 23 the bi s of buildin s nlring the cylindrical portion of the root require to be sulhciently nnissive and adequately footed to take the inward tension of the root members since in this construction there is no other means (as there is in the circular dome) by which the said tension may be otherwise resisted.

The type of roof depicted in Figure 22 closely resembles that described in detail in specification of British Patent 119339 of 1917 already granted to the present applicant.

Although in the examples given in the figures the domes have comprised an arc of less than a hemisphere and inthe case of the cylindrical root less than a semi-circle, such forms being generally more advantageous, it is possible to apply the system to a domed roof or" hemispherical form or in which the sides of the roof become vertical. Such a dome gives no resultant component at the anchorage as due to the tension of the roof members but has thedisadvantage or requiring more material and requiring a higher internal pressure to resist storms; in other words there is a greater tendency in such a dome for a cave-in to take place due to external wind pressure.

It is further possible to go beyond the hemisphere and to construct a dome of liloorish or Eastern type in which the sides of the roof turn inward and the tension of the roof members has an outward resultant. Domes in imitation of Moorish or Eastern designs may be produced by approximating the curve required in the manner described with reference to Figures 16 and 17. Further more shapes or pinnacles of fancy or fantastic form may readily be executed with a facility not attainable by ordinary methods of construction. I

The materials used in the case of domes of small size permit of a Wide choice, either steel or hemp. or manila ropes or hawsers are suitable, the selection depending largely upon the conditions as to permanence re quired, portability and cost. The fabric generally most appropriate is a closely woven canvas of low permeability dressed as may be required with oil and with an external coating of paint or dope. In some cases a coating of bitumen or tar may be applied; The degree of permeability re-' structure depicte- Cir qaired in any particular case depends upon Sea Island cottonor of linen fiber (flax) maybe employed. Balloon fabrics may be usedin certain cases, especially where low air permeability is wanted but such fabrics being of comparatively light weight I require to be well supportedby independent network or by a closer disposition of the 'ratlins as described with reference to Fig- ;ure 13. As already stated, forthe lantern,

where it is required to admit daylight, the

V fabric may be of transparent or translucent. materiah In addition to this glazed port holes may be fitted as described in British as already stated translucent canvas or fabspecification 119339 (1917). Alternatively ric may be employed for the main envelope in which case a very moderate degree of translucency'is all that is required, a degree not incons stent with adequate strength. vThe method of roofing buildings n1. ac-

1 cordance with the present invention is 'funthe building and may be said 'to form a negative load.

damentally diiferent from existing or known prior practice, many of the. conditlons, being inverted. Thus, ust as the Tordinary roof ofa building requires to be supported and forms a load to be carried by the'building itself and by the founda tion, a roof constructed in accordance w th the present invention actually tends to hit Consequently the footings and foundation are relieved of the major portion of their duty and. a considerable economyis effected in the building itself on this account alone'quite apart from the reduction of'the expenditure .on the roof structure; Beyond this there is a very definite limit to the" span of a steel roof or a steel dome and this limit has in some'of the largest existing structures been approached.

There is no definite theoretical limit to the size of a pressure supported roof and the practical limit in anycase betokens'that a span many times that known; to present l practice is possible. V

'lIfiVlllg now. described my inventiomwhat I claim as new and desire to secure by Letters Patent is 1. A building comprising an. endless rigid wall, a substantially dome-shaped flexible roof connected to said wall, and means for "introducing an aeri'form medium into the V enclosure formed by sald wall'and root un independent foundations and connected by der sufficient pressure to sustain the roof without the aid of interior supports.

2. A building as claimed'in claim 1 hav'- ing root. tension members secured to the roof, and "permanent anchorages carried by the wall. and attached to said roof tensioning members. F V 1 3. A building of the kind defined by claim 1 in which the roof comprises a fabric of low permeability to air retained by net work system of roping having terminal members adapted to besecuredto the wall, and an air lock forming a'means for entry and exit from the enclosure formed by the wall and roof.

l, 'Abuilding of the kind defined by claim 1 having roof tension members secured to the roof, permanent anchorages carried by the wall and attached to said roof tensioning members, "andan air-look arranged in the wall and forming a means of entrance and exit to and from the enclosure formed by the wall and roof. i V 5. A building of the kind defined by elaii l in which the roolis provided with a re tainiiw rope-work net comprising circumferential members disposed. like parallels of latitude and radial members disposed like meridians oi longitude, certain of the radial members being bifurcated, and a lantern mounted at the top of the roof and secured to said radial members. V c

6. A building comprising'in combination an endless rigid wall, a flexible roof secured to said wall and sustained in position only by air pressure within the enclosure formed by the wall and roof, said wall consisting of .a'system of masonry constructioncomprising a number of sections or blocks mounted on temporary renewable sections.

7. A building of thekind defined by claim 1 in which the wall consists of a reinforced masonry, structure including vertical reinforced bars combined with horizontal and vertical bars, and" anchorage members secured to'said bars and projecting "from the wall andlforming attached. V I V V V 8. A buildingot the kind defined by claim 1 provided with a passagehaving a rela 1 tively low ceiling so that people entering or leaving the building en masse form in eiiect a blockageor sealing of the passage and prevent loss or air pressure. 7

9. A building of the kinddefined by claim 1 having a. passage provided with a low ceiling and having exit doors arranged at its outerend and adapted toopen'outwardly.

10. A-buildirig of the kind defined by claim 1 :in'which the wall is provided with a number'of arch-shaped portions formed of reinforced masonry, and an anchorage system comprising vertical bars having inverted catenary members to which the roof meansto which the roof is is adapted to be attached, said catenary members extending across the arch-shaped portions of the wall.

11. A building of the kind defined by claim 1 in which the roof is provided at its top with a lantern having transparent portions to admit light to the enclosure formed by the wall and roof.

12. A structure for use with a flexible roof comprising a hub-shaped member and a rim-shaped member, spoke-shaped members connecting the rim and hub-shaped members, a flexible cover extending over the hub, spoke and rim-shaped members, sealing means secured to the hub-shaped member and engaging the flexible cover, and means carried by the hub-shaped member and adapted to form an anchorage for flexible "fabric which extends beyond said rimshaped members.

13. A building of the kind defined by claim 1 in which, a structural network arranged on the outer side of said root and comprising circumferential members and radial members secured to each other, a lantern provided at the top of the roof to which the upper ends of the radial members are secured, and means provided on the wall to which the lower ends of the radial members are secured.

14. A building of the kind defined by claim 1 inwhich, circumferential elements are arranged on the outer side of said roof,

and radial elements arranged between the circumferential elements and provided at their ends with loops through which the circumferential members pass.

15. A building of the kind defined by claim 1 in which the lower edge of the roof is provided with a flap which is secured to the inner upper edge portion of the wall for sealing the joint between the wall and roof and preventing the escape of air at this juncture.

16. A building comprising an endless wall formed of independently spaced masonry piers, temporary sections arranged between said piers, metal reinforcements provided in the wall and having anchoring means which extend beyond the wall, a flexible roof having its edge secured to said anchoring means, and means for forcing air into the enclosure formed by said wall and roof for sustaining the roof without the employment of interior supports.

.17. A building of the kind defined by claim 16 in which the roof is of substantially dome-shape and is provided at its top with a lantern, and a flexible network cover arranged on the exterior of said roof, secured to said lantern and having portions which engage said anchoring means.

In testimony whereof I have signed my name to this specification.

FREDERICK WILLIAM LANCHESTER. 

